Dressing apparatus for formed grinding wheels and the like



March 27, 1945. E. w. MILLER 2,372,597

DRESSING APPARATUS FOR FORMED GRINDING WHEELS AND THE LIKE Filed Jan. 19, 1942 5 Sheets-Sheet l I I r .41 [T ,f Z zfi/zzdi/flzifif 1,; W 5 ii j 71 Q 1 Z IT\K\\ I 4 March 27, 1945. E w MILLER 2,372,597

DRESSING APPARATUS FOR FORMED GRINDING WHEELS AND THE LIKE Filed Jan. 19, 1942 5 9 2 EV IIII'IM' I I, I, I'I'I'IIIIII March 27, 1945. 2,372,597

DRESSING APPARATUS FOR FORMED GRINDING WHEELS AND THE LIKE" E. w. MILLER Filed Jan. 19, 1942 3 eets-Sheet 3 w I I and the mechanism which imparts the compound movement to the dressing tool is organized to effect such variations of the base circle. The dressing tool is secured to a carriage l which is mounted movably on a carriage holder 2 and is constrained to move along the line de. The carriage holder 2 is pivotally mounted to swing around the axis a, and it also supports and carries a slide 3 guided to'move along a line hi which is parallel to the line de and is tangent to a circle BC centered on the axis a and of sub stantially larger diameter than the circle be. Attached to the slide 3 is an abutment or cam follower 4 which bears against the surface 5 of a stationary cam or former 6. The face 5 is'an involute of the circle BC.

A lever l, which is here called a ratio lever,

is connected by a pivot pin 8 with the slide 3 and is formed with a notch 9 which embraces a stud l secured to the carriage holder 2; the cen-' ter of which stud is in a line a-y', parallel to lines d-e and ibz', passing through the axis a. The ratio lever carries on one face a bar ll having a contact surface l2 parallel with the line of centers kZ of the pivot 8 and stud I0. The,

dressing tool carriage extends over or in front of the ratio lever actually, although it is represented in these diagrams as behind the ratio lever, for clarity, and carries a rearwardly projecting stud 13 which overlaps the contact-face.

[2. The center of stud I3 is in the line of centers k-l, and its radius is equal to that of stud l0.

' A spring, later described, is arranged to force the stud I3 against the contact face l2 and the abutment 4 against the surface of the former on;

cam. Stud I0 is the fulcrum of the ratio lever which reacts to the force thus exerted. The direction of force application on the dressing tool carriage and abutment 4 is toward the grinding wheel.

It may be assumed for this explanation that the dressing action is commenced when the carriage holder 2 is in the position of Fig. 15, and is carried on by swinging this holder counterclockwise to the position of Fig. 16. This is the":

logical direction when the apparatus is designed to form a surface of straight line profile adjacent to the rim of the wheel; although the curved zone may be, dressed by swinging in either direction. The abutment 4 .then travels upwardly along the surface 5 of the former and is displaced outwardly toprogressively greater distances from the axis a. The ratio lever 1, being then turned about the fulcrum stud It, moves the carriage I through proportional distances. The ratio between the movement thus given to the dressing tool along the line d--e and the movement of the abutment along the line 71-1 is equal to the ratio between the radii of the base circles be and BC. The dressing tool is thus caused to trace a curve which is an involute of the circle be. In Order to generate in like manner curves of other base circles, the carriage is shifted so as to alter the distance of the line de from the line a,7'; and the machine is provided with means, later described, for so shifting the carriage while maintaining the lines a- -y', d-e and hi parallel to one another at all times.

The foregoing explanation covers the design and use of the invention for generating involute' curves.

But the invention is not limited to that design and use only. It may be organized for generating a wide variety of other curves in the cutting areas of grinding wheels and other cutti ng tools, by the substitution of other formers for the one of involute outline shown here. Almost any curve may be employed, of either continuous 0r reversed curvature, and whether continuously curved or consisting of angularly related straight line in part or all of its extent; provided only that the cam outline is such that it can be traversed by a suitable cam follower without interference, and that interferences are not caused between the dressing tool, in its continuing motion, and previously dressed parts of the wheel face. The curve generated in the grinding wheel is similar and proportional to the cam face of the former.

For dressing the wheel with a straight line profile from the point p to the rim, the whole assemblage is allowed to descend from the position of Fig. 16 to that of Fig, 1'7. This is accomplished by a cam l4 associated with the holder 2, and a support IS on which the cam rests. The cam is capable of turning through a limited angle with respect to the holder about an axis which, during the traverse of the dressing tool along curve 0, coincides with the axisa. It has a descent from the point IE to the point 11, and in the rest of its circumference it is concentric with its axis. During the traverse of the dressing tool over the curve 0, the cam turns with the carriage holder and a concentric arc of its surface rests on the support 15. The cam is so designed that the point l6 of its surface arrives at the support l5 when the dressing tool reaches the point p. Then the holder is prevented from rotating further and cam I4 is independently rotated so that its descending surface permits descent of the dressing tool in a path which, compounded with the rotation of the grinding wheel, causes the zone from p to the rim of the wheel to be given a straight line profile. By sutiable design and operation of the cam, the location of the point p with respect to the base circle be may be controlled. Here the point p lies in that base circle and the profile of the grinding face from p to the rim is radial to the base circle. Variations from these characteristics may be made within the scope of the invention.

. In the operative apparatus or machine which .I have shown in these drawings for performing a rotatable shaft 24. The quill 23 and shaft 24 are coaxial and their common axis is substantially horizontal and intersects at right angles the axis of the trunnions I9, which is also horizontal.

The former 6 is rigidly secured to a part of the housing It. The dresser carriage holder 2, which is essentially a plate of extended area, has a hub portion 25 mounted on the front end of shaft 24,

which protrudes from the quill, and secured thereto by a pin 25 (Fig. 3). In the rear side of holder 2 is mounted slide 3 confined between guides 28 and 29 with interposed balls constructed 1 to guide the slide without backlash accurately in a prescribed path, and with silght frictional resistance. Slide 3 carries the abutment 4 at its rear side and the pivot pin 8 protruding from its The '-ratio lever is "contained within 'ajchamber 3| in the-holder '2, and the fulcrum "stud' Ill is The means for mountingthe-dressing tool" carriage l' on the hoIderZ, with capabilityfo'r the movements and adjustments previously described,

comprises the "following." A plate32 "is "mountedi" clamping bolts *34,t he heads' ofwhich occupy" undercutchannels clamping bolt; is passed into cheer a number" of holes 31 in the lower part of the holdefthrough a slot in a bridge 38 whichbeais' on both the plate-" By means? and 'holder.

throng des '46 and=41"on'the rear side of the p of th earriege an be aiffoi'ded'ibyl the micrometer: hand wheel 43.

needed; this may be obtained byfp l aein'g gau side f'o'f the carriag bed zz'an'd an abutment cylindrical blo'okof niatei iafllhaving a flatf face fit' the side toward the former and arranged rotation of the. crew; so

ewag 1:3

est-11m;

be n 'iir ffie such deviation to make tangenteontactwith thelatteron a line intersecting the line hiof th diagrams. The

abutment is clamped between resilient jawsof a Y holder EQ by means of a clamp screwfill and the holder oecupie's a guideway'inthe backof the slide}, in which it is secured by a bolt 6;; This bolt passes through a'slot'fiz in the slide and a nut 63on"the bolt overlaps the bounding walls of the slot A'threadedrod s4 is secured to t e" outer end of holder 59 and extends through a braeket'tfiwhich is secured to the outer en'd'of measure such adjustments,

The foam"H1,previouslymentionedas causing the j e ii i jiz e f t ews w e lie be dressed, is keye' l l! w ich "iits lrot lil. elthf than 12% a ce to he rea end of he qu lt an s'pol r' ed i'otatabB a t be ms"... 14 on the adj end hr the r t. reaandw h i su h" h h 's der 1 eiioebithei r v w i tens s suc ar is the 'sa le"asthat "whichcauses' rotation of the ,holder 2 f flqm the position shown in ffig 15 to that shown in Fig..16, Henee when torque is applied to the lquill to rotate it, by means of the worm and wheel'gearing in the direction indicated, the weight 8! causes the sh aft 24, and the dressing toolfholder to be rotated in the same direction at the same speed, whatever that speed may be.

.A stop abutmenttZ is secured to a portion of v the housing I8 adjacent to the qarrier 2, and lies' re 1150 in the path of a stop pin 83 which projects from the carrier. These parts are arranged to arrest rotation ofthe carrier when it arrives in the position indicated by Fig. 16, or, in other words, when the dressing tool comes to the locality on the 355 grinding Wheel'which has been ordained as the limit of the curved face 0. The'eam isarranged l6, of itsrecedingsur so that the beginning point face eaehes the support' l5 at thegsametimel I v w v A Then the carrier is prevented from rotating 928 4 shownlinlidotte e j'at 54 n i -z further, butoontinued rotation of the quill carries the; receding car n surface 1 6-47 across the sup: port 15, allowin the housing l8 to descend, under theaction of gravity; as to its portion next'to' the" grinding wheel; It should be noted that theaxis t9,about which the dressing tool then moves, is" parallel to the axis on which 'the' grinding wheel is -set to rotate while'beingdressed. Hence, although thepath of the dressing tool then I deviates imperceptibly from-a 'stra'ightline, yet" is of no importance," (and would still he of no importance even if muchgreater in degree), because the path of the dressing tool'lies of rotation of'the wheel. ryguid'ef element 84 projectstfromthe housing [8 between of the'trunnions in the plane two guide rolls 85 and -86 inounted with'theif axes d l e' ifi e 1 1 ".3 E i 5 l v W in d e f si pa ted.tet t i ;a off'jthefclamping'"bolts',*20 worm and geaf ine'chanisxn eonsistingpta worin a 'ed pt d'i ec ve r n 'secured to a flange i a V a ous n LG t. 'ee e Di?! 1? x e t n eto. thetpt hetwei etivd l u erl sen-a a dsmw r .16 n

thereof and s uppor ts a weight Bl, The arrange- 'norinally'bears against pin 15 and the parallel on a bracket 87 which i secured to the base 2|. The sides of the guide element 84 against which these rolls bear are in parallel planes perpendicular to the axis of trunnions 69. This guide means is located near to the working location of the dressing tool, at least much nearer thereto than the trunnions l9, and it accurately establishes the plane in which the dressing tool travels when making a zone of straight line profile in the grinding wheel.

The member [5, previously described as being the support on which the cam M rests, is here shown a a rod movable, freely endwise through the guide element 84 and supported in its turn by a stud 88 set into the base portion of bracket 81. The abutting faces of rod [5 and stud 88 are convex, and so is the end face of the rod which supports the cam; Thus, when the receding cam face permits descent of the housing, the guide element 84 passes downward along the rod, and the latter is free to slip across the face of stud 88 to the extent necessitated by the arcuate movement of the element 84 around the trunnion axis.

The principles of the apparatus last described are operable to form conical zones as well as plane zones in grinding wheels and the like. This may be done by locating the axis of trunnions l9 and the plane of the grinding wheel at an obl que angle of any desired degree to one another. In either case the profile of that part of'the wheel dressed while the housing turns about the trunnion axis is composed of straight lines.

What I claim and desire to secure by Letters Patent is:

1. A dressing apparatus for creating a prescribed profile in a cutting tool, comprising an angularly movable carriage holder, a carriage mounted on said holder with provision for movement in a path crosswise of the axis of angular movement of the holder, a dressing instrument on said carriage, a relatively stationary former having a cam surface which is a curve generated from a base circle concentric with said axis, an abutment carried by said carriage holder in engagement With said cam surface and being movable on the holder in a path tangent to said concentric circle, and a lever pivotally coupled with said abutment, carr age and holder.

2. A dressing apparatus for creatinga prescribed profile in a cutting tool, comprising an angularly movable carriage holder, a carriage mounted on said holder with provision for movement in a path crosswise of the axis of angular movement of the holder, a dressing instrument on said carriage, a relat vely stationary former having a cam surface which is a curve generated from a base circle concentric with said axis, an abutment carried by said carriage holder in engagement with said cam surface and being movable on the holder in a path tangentto said concentric circle, and a lever pivotally coupled with said abutment, carriage and holder, the carriage being adjustable on the holder to alter the distance of its path from the axis, and the pivot coupling of the carriage with the lever being adjustable at the same time and in proportional degree.

3. An apparatus of the character set forth. comprising a dressing tool, an angularly movable holder, a guide member on which said dress ng tool is supported movably and constrained to move in a given path transverse to the axis about which said holder is movable, which guide member is mounted on the holder adjustably with pro-- vision for displacement in directions transverse to both said axis and said path, whereby to vary the distance ofthe path from the axis, a relatively stationary cam, a cam follower supported movably on the holder in engagement with the cam, and proportional motion mechanism operatively engaged with the holder, dressing tool and cam follower arranged to transmit motion from said cam follower to the dressing tool.

4. A wheel dressing apparatus comprising a cam and a holder, one of which is stationary and the other is movable angularly about an axis, a cam follower supported movably on said holder in engagement with the cam to be displaced thereby relatively to the holder in consequence of relative rotation between th holder and cam, an adjustable guide on the holder, a dressing tool carri r movable along said guide, the paths of the carrier and cam follower being parallel to eachother and transverse to said axis, and the adjustability of the'guide being transverse to both paths and the axis, a lever pivotally connected to the holder and camfollower, and a shiftable pivotal engagement between said lever and the dressing tool carrier.

5. A wheel dressing apparatus comprising a cam and a holder, one of which is stationary and the other is movable angularly about an axis, a cam follower supported movably on said holder in engagement with the cam to be displaced thereby relatively to the holder in consequence of relative rotation between the holder and cam, an adjustable guide on the holder, a dressing tool carrier movable along said guide, the paths of the carrier and cam follower being parallel to each other and transverse to said axis, and the adjustability of the guide being transverse to both paths and the axis, a lever having fulcrum connection with the holder on a line radial to the axis and parallel to the before-mentioned paths, said lever being also pivotally connected with the cam follower on an axis lying in the path of the follower, and a pivot carried by the dressing tool carrier in shiftable engagement with the lever.

6. A dressing or truing apparatus for the purpose set forth, comprising a housing, a holder rotatably mounted on said housing for movement about an axis, said housing being displaceable in a direction transverse to said axis, a guide member mounted on the holder, a dressing tool carriage mounted on said guide with provision for movement in a line tangential to a circle centered on said axis, a former secured to the housing having a. cam face formed as a curve generated from a base circle concentric with said axis, a cam follower or abutment slidingly mounted on said holder for movement in a path parallel to that of the dressing tool carriage, a lever pivotally connected with said abutment and having fulcrum connection with the holder, said pivotal and fulcrum connections being in a line transverse to the paths of movement of the carriage and abutment with changing angularity relative thereto when the abutment traverses said cam surface in consequence of angular movement of the holder, said carriage guide being shiftable on the holder in directions transverse to the path of the carriage, and the carriage having simultaneously shiftable engagement with said lever centered in the path of movement of the carriage, means for swinging said holder through a limited arc, and means for causing displacement of the housing in the before stated direction when the holder has arrived at the prescribed limit of its swinging movement.

'7. A dressing or truing apparatus comprising a-pivotally supported housing, a quill rotatably mounted inrsai quill,

said quill rotatably contained therein; a holder secured to' the" shaft; a dressin'g tool carriage mounted-on said holder, mechanismcooperating j parting atranslativecomponent of "movement-to the carriage when the shaft and holder are ro 1 tat'ed; means for rotating thequill; yielding-means between the -housi'ng and"said "carriage for -im-' fdr-impa-rting rotation to th e -shaft simultane ously with the quill, and a stop for arresting'ro tation of the shaft-ata prescribed point and permitting continued rotation of the quill, the surface of said cam being concentric with the axis of the quill throughout the arc of rotation in which the shaft approaches said stop, and being eccentric to the axis through a further angle throughout which the quill is rotated after arresting of the shaft.

8. A dressing apparatus comprising a holder supported with provision for angular movement about an axis, a dressing tool carriage mounted on said holder with provision for displacement thereon in a path tangent to a circle concentric with said axis, means for swinging the holder about said axis, means actuated by the holder in its angular movement about said axis for simultaneously imparting a component of translation to the carriage for causing the dressing tool to trace a curve other than concentric with the axis, and means for causing displacement of the holder, carriage and pivot axis of the holder together in a substantially straight line, Whereby to cause movement of the dressing tool in a substantially straight line tangent to said curve.

9. A dressing apparatus for generating surfaces of involute profile in grinding wheels comprising a stationary former having an involute face curve, a holder supported for angular movement about the center of the base circle of said face curve, a follower supported and guide on said holder for movement in a path tangent to said base circle and being arranged to bear on the curved face of the former, a dressing tool carrier mounted on the holder with provision for guided movement thereon in a path parallel to that of said follower, and a ratio lever pivotally connected with the follower and having a fulcrum engagement with the holder and a pivotal engagement with the dressing tool carrier for imparting to the latter translative movements proportional to the translative movements of the follower.

10. A dressing apparatus for generating surfaces of involute profile in grinding wheels comprising a stationary former having an involute face curve, a holder supported for angular movement about the center of the base circle of said face curve, a follower supported and guided on said holder for movement in a path tangent to said base circle and being arranged to bear on the curved face of the former, a plate mounted on the holder with provisions for adjustment thereon in a path transverse to the path of said follower, a dressing tool carrier mounted movably on said plate and guided to move in a path parallel to that of the cam follower, a ratio lever having pivotal and fulcrum connections with the follower and holder and a contact surface extending in the same direction as the line of centers of said pivot and fulcrum connections, and

plane substantially radial to said a st'udi'on-tthe a' di essingitoo'l 'carri'er foverlappirrgn and engaging said-1 contact; surface for t'movingr;

said-* carrier i in: consequenc'ei of angular? move?- ments-fof" "the lever; said: stud being: movabl to? different positions along said contactsurface inl consequence of adjustmentsof said plate.

11'. A dressing apparatus for generating sun-- facesof involute profile in grinding wheels coma prising 'a stationary former having an: invo'lute.

face-curve; a-holder supported for -angular movethe: curve'd face of the former, a dressing tool carrier 5 mounted on "the holder with provision for guided movement th'ereonwin' a I path parallel to that of said follower, a ratio lever pivotally connected with the follower and having a fulcrum engagement with the holder and a pivotal en-, gagement with the dressing tool carrier for imparting to the latter translative movements proportional to the translative movements of the follower, and means for shifting said holder in a manner to cause displacement of its axis of angular motion in a plane substantially radial to said base circle.

12. A dressing apparatus for generating surfaces of involute profile in grinding wheels comprising a stationary former having an involute face curve, a holder supported for angular movement about the center of the base circle of said face curve, a follower supported and guided on said holder for movement in a path tangent to said base circle and being arranged to bear on the curved face of the former, a plate mounted on the holder with provisions for adjustment thereon in a path transverse to the path of said follower, a dressing tool carrier mounted movably on said plate and guided to move in a path parallel to that of the cam follower, a ratio lever having pivotal and fulcrum connections with the follower and holder and a contact surface extending in the same direction as the line of centers of said pivot and fulcrum connections, a stud on the dressing tool carrier overlapping and engaging said contact surface for moving said carrier in consequence of angular movements of the lever, said stud being movable to different positions along said contact surface in consequence of adjustments of said plate, and means for shifting said holder in a manner to cause displacement of its axis of angular motion in a base circle.

13. An apparatus for dressing grinding wheels, comprising a dressing tool, a holder on which said tool is supported with provision for linear movement relatively to the holder, said holder being mounted pivotally to turn about an axis at one side of the path thereon in which the dressing tool has. its linear movement, mechanism correlated with said holder and tool to cause the tool to move relatively to the holder in its path of linear movement when said holder is turned about said axis, and provisions whereby the distance between said axis and path may be altered.

,14. A dressing apparatus as set forth in claim 13, combined with correlated means for turning the holder and then causing the pivotal support of said holder, and therewith the holder and the dressing tool, to be shifted after the holder has arrived at a predetermined position in its angular movement.

15. A dressing apparatus for generating a prescribed profile in the active portion of a cutting tool, comprising a' dressing instrument, a carriage on which said dressing instrument is mounted, a holder for said carriage mounted to be angularly movable about an axis, having guide means for the carriage whereon the latter is translatively movable in a path transverse to said axis, means for causing the carriage to be so moved relatively to the holder when the holder is turned about said axis, and means for altering the position of said guide means on the holder so as to locate the path of translative movement of the carriage at different distances from said axis.

16. An apparatus of the character set forth, comprising an angularly movable holder, a dress ing tool carriage mounted on said holder with provision for translative movement relatively thereto in a path tangent to a, base circle concentric with the axis of angular movement of the holder, a dressing tool secured to said carriage, means controlled by th holder in the course of its angular movement for causing the carriage to be moved relatively to the holder in said tangent path at a rate such that the dressing tool traces a curve developed from such base circle, and means for shifting said carriage relatively to the holder and to the means by which the carriage is moved translatively so that the distance from such axis of the path in which the carriage moves and the rate of its translative movement are altered, whereby the dressing tool is enabled to generate the characteristic curve from a different 0 base circle.

EDWARD W. MILLER. 

